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Significant Underestimation of Gaseous Methanesulfonic Acid (MSA) over Southern Ocean
Yan, Jinpei,Jung, Jinyoung,Zhang, Miming,Xu, Suqing,Lin, Qi,Zhao, Shuhui,Chen, Liqi American Chemical Society 2019 Environmental science & technology Vol.53 No.22
<P>Methanesulfonic acid (MSA), derived from the oxidation of dimethylsulfide (DMS), has a significant impact on biogenic sulfur cycle and climate. Gaseous MSA (MSA<SUB>g</SUB>) has been often ignored in previous studies due to its quick conversion to particulate MSA (MSA<SUB>p</SUB>) and low concentrations. MSA<SUB>g</SUB>, MSA<SUB>p</SUB>, and nss-SO<SUB>4</SUB><SUP>2-</SUP> were observed simultaneously for the first time with high-time-resolution (1 h) in the Southern Ocean (SO). The mean MSA<SUB>g</SUB> level reached up to 3.3 ± 1.6 pptv, ranging from ∼24.5 pptv in the SO, contributing to 31% ± 3% to the total MSA (MSA<SUB>T</SUB>). A reduction of the MSA to nss-SO<SUB>4</SUB><SUP>2-</SUP> ratios by about 30% was obtained when MSA<SUB>g</SUB> was not accounted for in the calculation, indicating that MSA<SUB>g</SUB> was very important in the assessment of the biogenic sulfur contributions in the atmosphere. Mass ratios of MSA to nss-SO<SUB>4</SUB><SUP>2-</SUP> increased first and then decreased with the temperature from −10 to 5 °C, with a maximum value at the temperature of −3 °C. Positive correlations between MSA<SUB>g</SUB> to MSA<SUB>T</SUB> ratios and temperature were presented, when the temperature was higher than 5 °C. This study highlights the importance of MSA<SUB>g</SUB> for understanding the atmospheric DMS oxidation mechanism and extends the knowledge of MSA formation in the marine atmosphere.</P> [FIG OMISSION]</BR>
Numerical study on heterogeneous behavior of fine particle growth
FAN Fengxian,YANG Linjun,Yuan Zhulin,Yan Jinpei,Jo Young Min 한국입자에어로졸학회 2009 Particle and Aerosol Research Vol.5 No.4
PM2.5 is one of critical air pollutants due to its high absorbability of heavy metallic fumes, PAH and bacillary micro organisms. Such a fine particulate matter is often formed through various nucleation processes including condensation. This study attempts to find the nucleation behaviors of PM2.5 arisen from coal power stations using a classical heterogeneous Fletcher’s theory. The numerical simulation by C-language could approximate the nucleation process of PM2.5 from water vapor, of which approach revealed the required energy for embryo formation and embryo size and nucleation rate. As a result of the calculation, it was found that wetting agents could affect the particle nucleation in vapor condensation. In particular, critical contact angle relates closely with the vapor saturation. Particle condensation could be reduced by lowering the angles. The wetting agents aid to decrease the contact angle and surface tensions, thereby may contribute to save the formation energy. Key words : Particle nucleation, Fletcher’s theory, Particle wettability, Numerical simulation